Conventionally, there has been known a liquid supplying device provided with a cartridge in which ink is stored, a sub tank connected to a recording head, and a liquid flow passage and a gas flow passage which connects the cartridge and the sub tank. The cartridge is disposed vertically above the sub tank. The liquid flow passage and the gas flow passage connect the cartridge and the sub tank in the vertical direction. The liquid flow passage and the gas flow passage are opened to the lower surface of the cartridge and the upper surface of the sub tank, respectively. Further, the sub tank is provided with an air introduction opening that penetrates the sub tank, whereby gas flows the inside of the sub tank to be supplied to the gas flow passage from the air introduction opening.